SAN FRANCISCO , California -LRB- CNN -RRB- -- The `` Mona Lisa '' has long been shrouded in mystery , including one long-standing question about the famous lady : What happened to her eyebrows and eyelashes ?

A French engineer and inventor examined the famous painting with a camera of his own design .

Now , a French engineer and inventor says he 's uncovered part of the enigma .

Pascal Cotte announced at a press conference Wednesday that he has found definitive proof that when Leonardo da Vinci painted the original portrait he included `` Mona Lisa 's '' lashes and brows .

Cotte examined the world 's most famous painting using a high-definition camera of his own design .

The device scanned a 240-million pixel image using 13 light spectrums , including ultra-violet and infrared .

The resulting ultra-high resolution photograph of 150,000 dots per inch yielded a reproduction of the `` Mona Lisa 's '' face magnified 24 times . And there Cotte found the evidence he sought -- a single brushstroke of a single hair above the left brow . Watch as expert announces findings on `` Mona Lisa '' ''

`` One day I say , if I can find only one hair , only one hair of the eyebrow , I will have definitively the proof that originally Leonardo da Vinci had painted eyelash and eyebrow , '' said Cotte .

So , if she once had lashes , where did they go ? Possibly faded pigment , Cotte suggested , or possibly a poor attempt to clean the painting .

`` And if you look closely at the eye of ` Mona Lisa ' you can clearly see that the cracks around the eye have slightly disappeared , and that may be explained that one day a curator or restorer cleaned the eye , and cleaning the eye , removed , probably removed the eyelashes and eyebrow , '' he said .

Cotte 's high resolution camera led him to numerous additional discoveries about the enigmatic artwork .

The infrared layer of the image shows that the fingers of the `` Mona Lisa 's '' left hand were originally painted in a slightly different position than in the final portrait .

Cotte said the change in position was the result of a lap blanket held by Leonardo 's model . In today 's faded image the blanket is all but obscured , but the highly detailed camera detected the faded pigment .

`` It was really the first time that we have this kind of position of the arm , '' Cotte said , `` and after Leonardo da Vinci , thousands of painters have made a copy of this position but without understanding why we have this position . The real justification of the position of the wrist is to hold the blanket on her stomach . It 's really a great , for me , it 's really a great discovery . ''

One of the results of Cotte 's work is a `` virtual '' restoration of the painting , an exact replica showing the original colors as they would have looked when the painting was new .

The skin tones of Leonardo 's model appear as a warm pink and the sky behind her is a glowing blue , far different from the gray-green tint that covers the artwork today . That dark patina is the result of 500 years of aging , according to Cotte .

Cotte presented numerous other findings within the infrared layer he photographed .

The researcher said the `` Mona Lisa 's '' smile was originally slightly wider than it appears today , and , in fact , so was her entire face .

Leonardo kept this painting with him for more than a decade , and is said to have worked on it up until his death . The Renaissance artist once said , `` Art is never finished , only abandoned . ''

The results of Cotte 's study are on display at the Metreon in San Francisco , as part of the exhibit `` Da Vinci : An Exhibition of Genius . '' E-mail to a friend

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Scan yields a reproduction of the ` Mona Lisa 's ' face magnified 24 times

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Image reveals a single brushstroke of a single hair above the left brow

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Engineer suggests faded pigment could explain lack of lashes and brows

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A poor attempt to clean the painting could also have erased the features